Attachment-plug for electric heating devices



W. N. FURTHMANN.

ATTACHMENT PLUG FOR ELECTRIC HEATING DEVICES. I

APPLICATION FILED APR. 19 m9.

1,329,592. Patented Feb. 3,1920.

UNITED STATES PATENT OFFICE. A

WILLIAM N. FURTHMANN, OF CHICAGO, ILLINOIS, ASSIGNOR TO GRAY-HEATH COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION .OF ILLINOIS.

ATTACHMENT-PLUG FOR ELECTRIUHEATING DEVICES.

Specification of Letters Patent.

Patented Feb. 3, 1920.

- Application filed April 19, 1919. Serial No. 291,370.

To all whom it may concern: v

Be it known that I, WILLIAM N. FURTH- MANN, a citizen of the United States, residing at Chicago, in'the county of Cook and Statev of Illinois, have invented certain new and useful Improvements in Attachment- Plugs for Electric Heating Devices, of

' which the following is a specification.

Electric heating devices, such as toasters, sad-irons, and the like, are commonly equipped with contact terminals in the form of a pair of fingers or prongs, which enter sockets in a removable attachment plu on the end of the circuit wire, the sockets o the attachment plug carrying expansible metal contacts cooperating with the contact prongs or fingers of the heating device to close the circuit. 7

In the manufacture of such heating devices there is at present no standardization of the contact devices. In some cases the prongs take the form of blades, in other cases the prongs are substan tially square in cross section.- i-,In still other 4 cases the prongs are of an oblong rectangular form in cross section, and in still other instances they are substantiall circular in cross section. As a result 0 this, it has heretofore been necessary to provide difi'erent styles of attachment plug, each carrying expansible contact strips adapted to the particular form of the prongs or fingers of the heating device.- I

The principal object of the present invention is to provide an attachment plug of such a construction thatit shall be ada table to and usable with any and all of the ifler ent forms of contact prongs or fingers found on the venous-heating'devices in use; and

' panying drawing, in which Figure 1 1s a top plan view of the lower half of the body of the plug showing the hollow metallic contact relatively thin, flat pieces seated therein.

, Fig. 2 is an end View of the attachment plug, as seen from the right of Fig. 1.

' Fig. 3 is a cross-sectional view.

Fig. 4 is a perspective detail of one of the hollow longitudinally split contact pieces carried by the plug; and I Figs. 5, 6,' 7 and 8 are detail sectional views illustrating the adaptability of the device for cooperation with contact prongs or fingers of various cross-sectional forms. 7

Referring to the drawing, 9 and 10 designate the upper and lower mating halves of the body of the plug, which is made of any suitable insulating material, these halves being united by bolts 11. In the inner opposed faces of the body members 9 and-10 are formed depressions or seats 12 and 13 which, when the parts are united, form a pair of arallel sockets each of substantially diamond form in cross-sectio Directly in the rear of the sockets 12 and 13 are rectangular sockets 14 which accommodate the in ner ends or shanks of the longitudinally split contact pieces hereinafter described, and at the left hand end, as shown in Fig. 1 is a forked duct or passageway 15 to accommodate circuit wires 16.

Housed within the diamond-shaped sockets are the metallic contact pieces, each of which comprises a hollow metallic member 17 of substantially diamond formin crosssection and longitudinally split preferably in the plane of the major axis of its cross section, so as to be expansible transversely within the limits permitted by the socket itself which is of somewhat greater cross section than the contact piece itself. At the inner end of each contact piece is a flat shank 18 of double thickness, is passed the binding screw 19 for the circuit Wire 16. Preferably, and as shown in Fig. 4, each contact piece is formed of a pair of mating sections united through their stems or shanks 18 by the binding screws 19, the material used being hosphor-bronze, brass, or some other con ucting material having a springy or elastic quality.

" Figs. 5 to 8, inclusive, illustrate the adaptability of these hollow contact pieces to re ceive contact prongs or fingers of varying sizes and cross sectional forms. Fig. 5 illustrates the use of the device with a contact finger or blade 20 of relatively wide and thin form. Fig. 6 illustrates lts use with m naaaaoa a contact. finger 21 of substantially square rial having a pair of contact-holding sockets form in cross section. Fig. 7 illustrates its in one end thereof, and contact pieces use with a contact finger of oblong rectanhoused in said sockets and each comprising gular form; and Fig. 8 illustrates its use a pair of spring jaws each of semi-diamond with a contact finger 23 of circular form in shape in cross-section lying face to face, cross section. It will be observed that with said jaws at their inner ends having flat each of these difierent forms ofcontact finstems or shanks united by a binding screw.

. gers a plurality of line contacts are secured, 3. An electrical attachment plug, com- 7 the elastic jaws, of the contact piece springprising a body member made in mating ing apart slightly when the contact finger is halves, said halves having formed in their inserted, andthereby securing a strong fricmeeting "faces parallel recesses of semi-diational contact. mond form in cross-sectiomand the recesses I claim: otthe two halves when brought into register 1. An electrical attachment plug, comforming contact-holding sockets of diamond. prising a body member of insulating mateform in cross-section, contact pieces housed rial having a pair of contact-holding sockin said sockets and each comprising a pair ets in one end thereof, and contact pieces of spring jaws each of semi-diamond form housed in said sockets and each comprising in cross-section lying face to face, said jaws a hollow metallic member of substantially being of less cross-sectional dimensions than diamond shape in cross-section and split said sockets, and said jaws. at their inner longitudinally in the plane of the major axis ends having flat integral stems or shanks of its cross-section. united by a binding screw, and means for 2. [an electrical attachment plug, comuniting the halves oi said body member. prising a body member of insulating mate- VVliLLllAll l N. FURTHMANN. 

